Synthesis and Characterization of Calcium Magnesium Phosphate (CaMg(HPO4)2) Nanoparticle Material Made from Dolomite

Abstract

Dolomite is a mineral with potential as an alternative material to enhance fertilizer quality. Traditional fertilizers often suffer from low nutrient use efficiency, as much of the applied nutrients are lost before being absorbed by plants, leading to economic and environmental losses. Nanofertilizers offer a solution by increasing nutrient uptake efficiency due to their small particle size and large surface area. This study aims to characterize calcium magnesium phosphate nanoparticles synthesized from dolomite and evaluate their elemental solubility in water. The synthesis involved dissolving dolomite at five different weights (20, 30, 40, 50, 60 grams) and reacting it with varying volumes of disodium phosphate (400–1200 mL). SEM analysis revealed a thin plate or needle-like crystal structure. The best composition—20 g dolomite and 1200 mL disodium phosphate—resulted in a product containing 22.13% calcium and 19.57% phosphorus, with an average Ca/P ratio of 1.005, as shown by EDX. Magnesium was not present in the precipitate due to the synthesis pH (4–6), which is below the optimum pH (8–9.5) for magnesium precipitation. BET analysis confirmed a particle size of 96 nm, classifying the material as a nanomaterial. Solubility tests suggest the material functions as a slow-release fertilizer. Given its calcium and phosphorus content and nanoscale structure, this material shows strong potential as a high-quality, multinutrient nanofertilizer that can improve nutrient absorption and support sustainable agriculture.